Lower Level: A program that controls the execution of application programs and an interface between applications hardware
Primary Controls
Control, Error Detection and Response, Accounting
Different Types of Operating Systems:
Personal
Virus Software
Screensaver
Examples
Window 98, Window 2000, Mac OS, Linux
Work Group
Status of accounts
Passwords and Activity
Resource usage
Examples
Windows NT Server, Windows XP, Mac OS Server, Linux
Enterprise
Archival Operations
Job Status
Data Mining
Examples
Windows XP, Windows NT Server, Solaris
Consumers
Ex:
Linux
Windows XP Embedded
Windows CE Net
OS Timeline
Frist Generation 1945-1955
Vacuum tubes
Plug boards
Second Generation 1955-1965
Transistors
Batch Systems
Third generation 1965-1980
integrated circuits
multiprogramming
Fourth 1980-2005
large scale integration
personal computers
Next 2005 - ?
System connected by high-speed networks
wide area resource management
cloud computing
File Systems (a data structure on a disk that holds files)
Computer hard drive components (SADRAC)
spindle
arm
disk (holds information)
read/write head (reads and writes info. on disk)
actuator
circuit board
File systems in different OS have different internal structures
3 ways to allocate space on a hard drive
Contiguous- requires each file to occupy a set of contiguous blocks on the disk
simple- file designations only need to include starting location and how many blocks are required
Dynamic storage allocation is difficult
External fragmentation is difficult
Files can't grow
Linked
Solves contiguous allocation problem
Each file is a linked list of disk blocks scattered anywhere on the disk
no external fragmentation
(FAT) file allocation table used to support direct access
Indexed
Solves external fragmentation and size declaration issues with contiguous allocation
Each file contains index block
Suffers from wasted space
The operating system uses a file system to keep track of the names and locations of files that reside on a storage medium
Disk sectors are grouped into clusters
FAT(File Allocation Table)- an operating system file that maintains a list of files and their physical location on the disk (of a hard drive)
Introduced with MSDOS in 70s
Evolved in response to change in names of files and structure, and increasing size of hard drives
3 types of FAT file systems
1. FAT 12
2. FAT 16
3. FAT 32
Deleting a file means the OS removes the file name and makes it seem empty, but the information is still there
MFT(Master File Table)- an array of records holding attributed for a different file
Fragmentation- as files are added and deleted, files tend to scatter across the disk space
This slows performance of reading and writing
Defragmentation reorders files
Fragmentation
Internal-allocates storage without using it
External- free space divided into small pieces over time
Data- data broken into memory into many small pieces due to external fragmentation
WinFS
allows for a "flattened" non-hierarchical system to search for files based on attributes like the date
Can understand arbitrary defined sets of data like "e-mail" "photo" "calendar"
Benefits of winFS:
data is easily found
information is organized in a way that makes logical sense to people
integrated view of information
Use of metadata tags and relations
Keywords:
Desktop- A computer designed for desktop use; usually comprises, at a minimum, a central processing unit (CPU), a monitor, and a keyboard as separate units, connected by special cables.
DNS- Refers to a Domain Name Server. A dedicated server or a service within a server that provides DNS name resolution in an IP network. It turns names for Websites and network resources into numeric IP addresses. DNS servers are used in large companies, in all ISPs and within the DNS system in the Internet, a vital service that keeps the Internet working.
File Server- A high-speed computer in a network that stores the programs and data files shared by users. It acts like a remote disk drive. The difference between a file server and an application server is that the file server stores the programs and data, while the application server runs the programs and processes the data.
Server- a server is a computer system that provides services to other computing systems ”called clients” over a network. The term server can refer to hardware (such as a Sun computer system) or software (such as an RDBMS server).
FAT- An area on a hard disk or floppy disk where information is stored about the physical location of each piece of every file on the disk and about the location of unusable areas of the disk. File Allocation Table (FAT) is a partially patented file system developed by Microsoft for MS-DOS and is the primary file system for consumer versions of Microsoft Windows up to and including Windows Me.
NTFS- (NT File System) An optional file system for Windows NT, 2000 and XP operating systems. NTFS is the more advanced file system, compared to FAT32. It improves performance and is required in order to implement numerous security and administrative features in the OS.
Virtual Memory- An imaginary memory area supported by some operating systems (for example, Windows but not DOS) in conjunction with the system hardware. You can think of virtual memory as an alternate set of memory addresses. Programs use these virtual addresses rather than real addresses to store instructions and data.
Hard Drive- The primary computer storage device, which spins, reads and writes one or more fixed disk platters.
CD-ROM/RW Drive- A device that holds and reads CD-ROM discs. CD-ROM drives, which today typically means a CD-RW drive that is a combo CD-ROM, CD-R and CD-RW drive, come in a variety of speeds.
Fragmentation- Refers to the condition of a disk in which files are divided into pieces scattered around the disk. Fragmentation occurs naturally when you use a disk frequently, creating, deleting, and modifying files.
Floppy- Short for floppy disk drive (FDD), a disk drive that can read and write to floppy disks.
- Lower Level: A program that controls the execution of application programs and an interface between applications hardware
- Primary Controls
- Control, Error Detection and Response, Accounting
Different Types of Operating Systems:Personal
- Virus Software
- Screensaver
- Examples
- Window 98, Window 2000, Mac OS, Linux
Work Group- Status of accounts
- Passwords and Activity
- Resource usage
- Examples
- Windows NT Server, Windows XP, Mac OS Server, Linux
Enterprise- Archival Operations
- Job Status
- Data Mining
- Examples
- Windows XP, Windows NT Server, Solaris
ConsumersOS Timeline
File Systems (a data structure on a disk that holds files)
3 ways to allocate space on a hard drive
- Contiguous- requires each file to occupy a set of contiguous blocks on the disk
- simple- file designations only need to include starting location and how many blocks are required
- Dynamic storage allocation is difficult
- External fragmentation is difficult
- Files can't grow
- Linked
- Solves contiguous allocation problem
- Each file is a linked list of disk blocks scattered anywhere on the disk
- no external fragmentation
- (FAT) file allocation table used to support direct access
- Indexed
- Solves external fragmentation and size declaration issues with contiguous allocation
- Each file contains index block
- Suffers from wasted space
The operating system uses a file system to keep track of the names and locations of files that reside on a storage mediumFragmentation- as files are added and deleted, files tend to scatter across the disk space
This slows performance of reading and writing
Defragmentation reorders files
Fragmentation
WinFS
Benefits of winFS:
Keywords:
Desktop- A computer designed for desktop use; usually comprises, at a minimum, a central processing unit (CPU), a monitor, and a keyboard as separate units, connected by special cables.
DNS- Refers to a Domain Name Server. A dedicated server or a service within a server that provides DNS name resolution in an IP network. It turns names for Websites and network resources into numeric IP addresses. DNS servers are used in large companies, in all ISPs and within the DNS system in the Internet, a vital service that keeps the Internet working.
File Server- A high-speed computer in a network that stores the programs and data files shared by users. It acts like a remote disk drive. The difference between a file server and an application server is that the file server stores the programs and data, while the application server runs the programs and processes the data.
Server- a server is a computer system that provides services to other computing systems ”called clients” over a network. The term server can refer to hardware (such as a Sun computer system) or software (such as an RDBMS server).
FAT- An area on a hard disk or floppy disk where information is stored about the physical location of each piece of every file on the disk and about the location of unusable areas of the disk. File Allocation Table (FAT) is a partially patented file system developed by Microsoft for MS-DOS and is the primary file system for consumer versions of Microsoft Windows up to and including Windows Me.
NTFS- (NT File System) An optional file system for Windows NT, 2000 and XP operating systems. NTFS is the more advanced file system, compared to FAT32. It improves performance and is required in order to implement numerous security and administrative features in the OS.
Virtual Memory- An imaginary memory area supported by some operating systems (for example, Windows but not DOS) in conjunction with the system hardware. You can think of virtual memory as an alternate set of memory addresses. Programs use these virtual addresses rather than real addresses to store instructions and data.
Hard Drive- The primary computer storage device, which spins, reads and writes one or more fixed disk platters.
CD-ROM/RW Drive- A device that holds and reads CD-ROM discs. CD-ROM drives, which today typically means a CD-RW drive that is a combo CD-ROM, CD-R and CD-RW drive, come in a variety of speeds.
Fragmentation- Refers to the condition of a disk in which files are divided into pieces scattered around the disk. Fragmentation occurs naturally when you use a disk frequently, creating, deleting, and modifying files.
Floppy- Short for floppy disk drive (FDD), a disk drive that can read and write to floppy disks.